Telkom SA SOC / telkom vdsl billing

I have a 20mb uncapped vdsl home package from telkom. The line works perfectly no complaints there, but there billing and customer service department is terrible.

The line was installed mid may 2018. The monthly bill should be r1008 pm roughly. I have paid a total of r9500 for 6.5 months. So telkom still owes me a pretty penny. Now I refuse to pay them as I have been double billed for january again "r2200". Now they are threatening to suspend the line again. I have submitted around 4 cases already to their billing department. They send a message that says it has been resolved. Now I have been billed correctly for february, however the double bill for january still stands and I still need to be credited for the amount I have over payed in 2018 to get my internet back online.